Two-cycle engine lubricant and fuel



United States Patent 3,409,553 TWO-CYCLE ENGINE LUBRICANT AND FUEL Bobby N. Scoggins and Lloyd P. Foster, Kingsport, Tenn., assignors to Eastman Kodak Company, Rochester, N .Y., a corporation of New Jersey No Drawing. Filed Feb. 1, 1966, Ser. No. 523,967 Claims. (Cl. 252-57) ABSTRACT OF THE DISCLOSURE A two-cycle engine lubricant and fuel containing di- (Z-ethylhexyl) cyclohexane-1,2-dicarboxylate or di(Z-ethylhexyl) cyclohexane-1,3-dicarboxylate.

This invention relates to improved two-cycle engine lubricants and to improved two-cycle engine fuels containing the improved lubricants. More particularly, this invention relates to novel two-cycle engine lubricants comprising a mixture of petroleum lubricating oil and at least one of the esters di(Z-ethylhexyl) cyclohexane-1,2-dicarboxylate or di(Z-ethylhexyl) cyclohexane-1,3-dicarboxylate and to the use of these novel lubricants in fuels for two-cycle engines.

Two-cycle engines are lubricated by mixing the lubricant and the fuel for the engine. The mixture of fuel and lubricant passes through the crankcase of a two-cycle engine, where it lubricates the moving parts of the engine, and then flows through intake ports into the combustion chamber of the engine where the mixture of fuel and the lubricant is burned. The burned mixture of fuel and lubricant is then exhausted from the combustion chamber of a two-cycle engine through exhaust ports. The use of lubricants for two-cycle engines in this manner imposes rigorous requirements which an ideal lubricant must possess. Thus, a two-cycle engine lubricant must provide adequate lubrication for the moving parts of the engine. The lubricant must then pass into the combustion chamber without leaving objectionable deposits in the intake ports and must burn cleanly in order to avoid fouling the combustion chamber and spark plug with undesirable deposits and to avoid fouling of the exhaust ports. At the present, petroleum lubricating oils are employed as lubricants for two-cycle engines. In general, the best oils now available still do not meet the requirements of an ideal two-cycle engine lubricant. Because of the rigorous combination of properties which a two-cycle engine lubricant must possess, it is unlikely that an ideal two-cycle lubricant will ever be discovered.

We have, however, discovered an improved two-cycle engine lubricant which is substantially superior to known two-cycle engine lubricants. Our improved lubricant comprises a mixture containing mineral oil, i.e., a petroleum lubricating oil, and at least one of the esters di(Z-ethylhexyl) cyclohexane-1,2-dicarboxylate or di(2-ethylhexyl) cyclohexane-1,3-dicarboxylate in which the ratio of mineral oil to ester is from about 95:5 to about 50:50. Preferably the ratio of mineral oil to ester is from about 90:10 to about 70:30. Also included within the scope of our invention are the novel twocycle engine fuels which result when our novel two-cycle engine lubricant is mixed with gasoline. Our novel fuel compositions generally comprise a mixture of gasoline and lubricant in a gasolinezlubricant ratio from about 16:1 to about 100:1.

The mineral oils which are preferred in preparing the compositions of our invention are the conventional petroleum lubricating oils which have heretofore been employed for lubricating two-cycle engines. In general, any hydrocarbon petroleum lubricating oil suitable for lubrication of a reciprocating engine can be used in our novel comice positions. The petroleum lubricating oil can contain any of the conventional additives which are commonly employed in lubricants, e.g., corrosion inhibitors, detergents, etc. The hydrocarbon lubricating oils having a Saybolt Universal viscosity at 100 F. of from about to about 1 000 seconds are typical of those used in the compositions of our invention with such mineral oils having a Saybolt Universal viscosity at 100 F. of about to about 300 seconds being preferred.

As pointed out hereinbefore, the major shortcomings of two-cycle engine lubricants now being employed are inadequate lubrication of the moving parts of the engine, blocking of the intake and exhaust ports of the engine, deposits within the combustion chamber of the engine, sticking of the piston rings of the engine, and failure of the spark plugs in the engine because of deposits of combustion products. In discovering our improved two-cycle engine lubricants and two-cycle engine fuels, we conducted a number of tests employing commercially available twocycle engine lubricants and possible alternative lubricants for two-cycle engines. We have found that the lubricants of our invention are unexpectedly superior to both the commercially available lubricants and the other lubricants which we evaluated. For example, the lubricant compositions of our invention comprising a mineral oil and at least one of the esters di(Z-ethylhexyl) cyclohexane-1,2- dicarboxylate or di(Z-ethylhexyl) cyclohexane-1,3-dicarboxylate are superior to mineral oils when used alone or to the same esters when used alone. This superiority of our lubricants is entirely unexpected. Furthermore, our lubricant compositions are unexpectedly superior to similar compositions which contains esters different from those employed in the compositions of our invention.

We have conducted a number of tests of two-cycle engine lubricants according to the following procedure. A two-cycle engine was coupled to a 1500 watt generator which provided the load for the engine. The engine, using a mixture of commercially available gasoline and the lubricant being tested, was run at full throttle for a period of 55 minutes and was then allowed to idle for five minutes. This test was continued for a period of 50 or hours. When mineral oil was used in the tests, we employed a commercially available two-cycle engine lubricant sold under the trademark RPM. At the end of the test the engine was disassembled and inspected to determine if the lubrication had been satisfactory, the extent of blockage of intake and exhaust ports, the extent of combustion chamber deposits, the extent of piston ring sticking, and the extent of spark plug fouling. The performance of the lubricant was then rated on a scale of from about 1 to 5 with 1 being poor and 5 being excellent. The rating for the lubricant took into account all of the previously discussed factors and also allowed for the duration of the test. Thus, the overall rating provides an accurate indication of the relative performance of each of the lubricants which was tested.

The results for the compositions of our invention which were obtained in the tests are summarized in Table I.

3 The results obtained for the other compositions tested are summarized in Table II.

TABLE II Ratio, Duration Lubricant Gas Luof Test Rating bricant (hours) 100% Mineral Lubricating Oil 25:1 100 1 100% di(Z-ethylhexyl) eyclohexa 1,3-dicarboxylate 25:1 100 2 100% di(Z-ethylhexyl) cyclohexane- 1,2dicarboxylate 25:1 100 Y 2 100% di(2-ethylhexyl) cyclohexane- 1,4-diearboxylate 25:1 100 l-2 20% di(Z-ethylhexyl) cyclohexanel,4-dicarboxylate. 25: 1 1C0 2 80% Mineral Lubricating Oil 100% dioctyl phthalate 25:1 100 2 20% dioctyl phthalate 100 2 80% Mineral Lubricating Oil 100% di(2-ethylhexyl) adipate-.. 25:1 100 2 20% di(2-ethylhexyl) adipate 100 2 80% Mineral Lubricating Oil 5% di(2-ethylhexyl) adipate dioetyl phthalate 25:1 100 2 80% Mineral Lubricating OiL. 100% di(2-ethylhexyl) sebacate 25:1 100 12 di(2-ethylhexyl) sebacate n} 100 1-2 80% Mineral Lubricating Oil- 20% 2,2,4-trimethyl-pentane-1,3-diol dipelargonate. 50:1 50 2 80% Mineral Lubricating Oil 20% cyclohexane-Ltdimethanol bis(2-ethylhexanoate) 50:1 50 2 80% Mineral Lubricating Oil 20% di(2-ethylisohexyl) cyclo- 50 1 hexane-1,2-dicarb oxylate. 50: l 80% Mineral Lubricating Oil 20% 2,2,4,4-tetrarnethyl-1,3-cyclobutanediol-bis(2-ethyl hexanoate) 100:1 50 1 80% Mineral Lubricating Oil As can be seen from the foregoing tables, lubricant compositions comprising mineral lubricating oil and at least one of the esters di(Z-ethylhexyl) cyclohexane-1,2- dicarboxylate or di(Z-ethylhexyl) cyclohexane-1,3-dicarboxylate are markedly superior to the other compositions which were tested. Especially preferred among the embodiments of our invention is the lubricant composition comprising a mineral oil and the ester di(Z-ethylhexyl) cyclohexane-1,2-dicarboxylate.

The unexpectedness of the superiority of our lubricant compositions is apparent from the preceding tables. Thus, it can be seen that our compositions are superior to a lubricating mineral oil when used alone or to either of the esters of our invention when used alone. Equally surprising is the fact that our compositions are markedly superior to compositions comprising a mineral oil and an ester other than one of the esters employed in the compositions of our invention, for example, di(Z-ethylhexyl) cyclohexane-1,4-dicarboxylate.

Although the invention has been described in considerable detail with particular reference to certain preferred embodiments thereof, variations and modifications can be effected within the spirit and scope of the invention as 4 described hereinbefore and as defined in the appended claims. l

We claim:

1. An improved two-cycle engine lubricant comprising a mixture containing mineral lubricating oil and at least one of the esters (a) di(Z-ethylhexyl) cyclohexane-1,2-dicarboxylate or (b) di(Z-ethylhexyl) cyclohexane-l,3-dicarboxylate, the ratio of mineral oil to ester in said lubricant composition being from about 95:5 to about 50:50.

2. The improved lubricant composition of claim 1 in which the ester is di(Z-ethylhexyl) cyclohexane-1,2-dicarboxylate.

3. The improved lubricant composition of claim 1 in which the ester is di(Z-ethylhexyl) cyclohexane-1,3-dicarboxylate.

4. The improved lubricant composition of claim 1 in which the ratio of mineral oil to ester is from about 90:10 to about :30.

5. The improved lubricant composition of claim 4 in which the ester is di(2-ethylhexyl) cyclohexane-1,2-dicarboxylate.

6. The improved lubricant composition of claim 4 in Which the ester is di(Z-ethylhexyl) cyclohexane-1,3-dicarboxylate.

7. An improved two-cycle engine fuel composition comprising gasoline in admixture with a lubricant composition comprising a mixture containing mineral lubricating oil and at least one of the esters (a) di(Z-ethylhexyl) cyclohexane-1,2-dicarboxylate or (b) di(Z-ethylhexyl) cyclohexane-1,3-dicarboxylate, the ratio of gasoline to lubricant composition in said fuel composition being about 16:1 to about 100:1 and the ratio of mineral oil to ester in said lubricant composition being about 95:5 to about 50:50.

8. The improved two-cycle engine fuel composition of claim 7 in which the ratio of mineral oil to ester in the lubricant composition is from about :10 to about 70:30.

9. The improved two-cycle engine fuel composition of claim 8 in which the ester in the lubricant composition is di(Z-ethylhexyl) cyclohexane-l,2-dicarboxylate.

10. The improved two-cycle engine fuel composition of claim 8 in which the ester in the lubricant composition is di(Z-ethylhexyl) cyclohexane-1,3-dicarboxylate.

References Cited UNITED STATES PATENTS 3,235,494 2/1966 Piatt et a1. 4458 XR DANIEL E. WYMAN, Primary Examiner.

W. J. SHINE, Assistant Examiner. 

